Alaria americana

Alaria americana is a species of a trematode in a family Diplostomatidae.

Alaria americana is a three- host trematode that lives as adults in the intestine of the dog definitive host. Eggs are passed in faeces and hatch in water, releasing miracidia which penetrate the helisomid freshwater snails (first intermediate host) and develop through the sporocyst stage into cercariae. Cercariae released from snails actively penetrate the second intermediate host (tadpoles) becoming infective mesocercariae in about two weeks. In the tadpole or in the frogs (following the metamorphosis), mesocercariae accumulate and may be ingested by a number of paratenic hosts (e.g., other frogs, snakes) or directly by the definitive host.